Light-bulb Filaments: Brightness and Internal Reflections in Cycles
A few things you might try:


The color of your background will make significant difference when trying to see the internal reflections. I recommend making the background color the same color as the photo. With a light background like you have now, any light reflecting inside the bulb will be greatly diminished in terms of visibility. Here's an example:


The shape of the bulb will play a very important role in the amount of reflection you get inside the bulb. For example:



So, if you can model your lightbulb to have the exact same shape as the one in the photo, you should get similar reflections. 
In addition, the IOR (Index Of Refraction) setting plays a large role in how much reflection is shown inside the bulb:

With an IOR of 1.0:


The same bulb with IOR of 3.0:

Yet another factor that can influence the amount of reflection is the thickness of the glass. If the bulb is a simple lightbulb-shaped mesh with a Glass material, then Blender will consider it a solid piece of glass, like a crystal ball, and this will significantly influence how light passes through it. In addition, if the bulb is a solid piece of glass, that could be one reason why there is no reflection inside the glass -- there is no inside face for the light to reflect off of. Ironically, in order to make the bulb hollow, the solution here is to add a Solidify modifier (as described below) to the bulb -- this will give the bulb mesh a very thin thickness and leave the rest hollow, thus allowing light to pass through the glass like a normal lightbulb rather than as a solid piece of glass: 


The camera angle in relation to the faces of the bulb will also play a significant role in how much light reflects into the camera:  


In the end, I found the following settings to give a significant improvement in the internal reflections:


Add a Solidify modifier to the bulb and set the Thickness to 0.01 or something similar:
Select bulb  → Object Properties panel → Modifiers tab → Solidify  → Thickness  → 0.01
Then setting the IOR on the glass bulb to 5.0 or so:
Select bulb  → Object Properties panel → Materials tab → IOR → 5.0
Setting the filament's emission Strength to 3000
Select filament  → Object Properties panel → Materials tab → Surface section → Strength   → 3000
Changing the filament's color to something like the following RGB and HSV values:
Select filament  → Object Properties panel → Materials tab → Color


 

This resulted in the following render:


The fact that the shape of the glass and also the thickness of the glass play significant roles in creating more realistic reflections made me think that in order to achieve photo-realistic results, the physical properties of the mesh models should be physically accurate representations of the objects being modeled. I'm no expert on photo-realism at all, but this just occurred to me and might help in your quest for realism.  

In this regard, you might explore setting the filament's color based on it's temperature in Kelvin with the Blackbody node in the Node Editor:



I'm not sure this is necessary, though, but you might consider it.